The present invention relates to a suction device, in particular for emergency medical purposes, which can be used for the withdrawal by suction of aspirate or foreign substances in the oral or nasal cavity of a patient requiring resuscitation.
Frequently in medical emergencies, the patient ingests foreign substances that accumulate in the oral/nasal cavity. For instance, in drowning persons, water or sludge may enter the oral/nasal cavity, and it frequently happens that unconscious patients requiring resuscitation vomit and aspirate the vomitus. In cases of trauma to the head, bleeding into the oral/nasal cavities can occur, and blood and clots can block the airway. In these circumstances, it is of primary importance to keep the airway open and free of accumulations of foreign substances or vomitus. Airway management is particularly important in the emergency medical field, where the patient or victim is remote from a hospital and hospital equipment. In this environment, the suction devices must be portable and capable of withdrawing whatever aspirate or substance may have accumulated in the oral or nasal cavities of the patient.
Suction devices of the type under discussion will form an integral part of first aid equipment used by emergency medical personnel. These suction devices must be as small and as lightweight as possible since they are to be used under a variety of conditions and in a variety of locations. In order to be an effective emergency unit for field use, a suction device must comply with certain minimum standards, such as those established by the Emergency Care Research Institute, as reported in an article entitled "portable Suction Sources" in the March, 1978 issue of "Health Devices", Vol. 7, No. 5, as set forth in the March, 1985 issue of "Jems" in an article by Thom Dick entitled "Suction Devices: A Guide to Emergency Field Aspirators", and as defined in ASTM Designation F960-86 "Standard Specification for Medical and Surgical Suction and Drainage Systems" published in March, 1986. The above-mentioned articles in the periodicals "Health Devices" and "Jems", as well as the ASTM Designation, are incorporated by reference herein, including their discussions of the operation of medical suction devices.
In general terms, the "JEMS Suction Model" described in the above-identified March, 1985 issue of "Jems" illustrates the optimum suction device. According to the Jems standard, the device should provide a suction level for oropharyngeal suctioning of up to 500 mm Hg at full airflow with the collection bottle in place, although a typical value of 300 mm Hg is acceptable. The device should reach this maximum suction level within 3 seconds of initiation. The free flowrate should be at least 30 liters per minute (lpm). so that the patient can be fully suctioned in as short a time as possible to reduce the risk of asphyxiation and the corrosive effects of vomitus or even emesis collected in the airways. Since aspirate and foreign substances can accumulate in the lungs and in the nasal cavities, the portable suction device should be capable of providing a free flow rate of 25 lpm at a lower suction level of around 100-150 mm Hg, such as for endotracheal suctioning, to prevent damage to the delicate mucosa linings. The collection receptacle for the aspirate should be unbreakable and have adequate capacity to hold the aspirate, typically between 500 and 1,000 milliliters (ml.).
According to the Jems standard, the optimum suction device should be compact and lightweight, since the medical personnel may be required to transport the suction device directly to an accident site where access is limited and difficult. The suction apparatus must be reliable and capable of providing a sustained suction for at least 60 minutes without being fouled by the aspirate or foreign substance being suctioned. The unit should also be capable of short-term intermittent use necessary to reduce the risk of hypoxia as the suction device removes more air than the patient can breathe. An optimum apparatus should have easily and quickly replaceable components, in particular the collection receptacle in the event the receptacle is overflowed. The device should further be protected from damage to its hardware, particularly metal components, should an overflow occur.
Portable suction devices come in a variety of designs, including manual pumps, gas powered devices, and battery powered electric devices. The vacuum source or pump, is also available in a variety of types, such as diaphragm, double-action piston, peristaltic, and rotary vane devices. Representative devices are described in the "Health Devices" and "Jems" publications incorporated by reference into this specification.
To applicant's knowledge, none of these prior art devices combines a modular design that is compact and lightweight with a suction system that is virtually leakproof and that is economical to dispose of after each use. The vast majority of the prior art devices have a very limited range of orientations in which the suction device can be operated without leakage into the electrical and mechanical components of the apparatus. Furthermore, these devices carry with them the risk of cross-contamination of the medical technician who must remove and clean the collection receptacle and suction equipment after each use. This can be a particular concern where the patient is carrying a highly communicable and contagious disease, under which circumstances it is preferable to reduce the risk of contact with the suctioned aspirate or foreign substance. Moreover, none of these suction devices satisfy the optimum criteria established for the "JEMS Suction Model" generally described above.